I don't usually bother writing reviews, but our stay at Casa do Rio deserves one. Our host, Carlos, was fantastic - very welcoming and offered to help us with whatever we needed. He arranged for us to visit their vineyard for an afternoon by the pool followed by a port tasting and then dinner, they even arranged transport for us.
Room was small but clean, bed was perfectly fine and the AC did it's job. We booked a room with a shared bathroom which was also good. There is a kitchen with the basic stuff if you want to cook.
All in all a great experience in Douro Valley!